From the Golden Sun side, Isaac could be a popular character in Naruto Golden Sun fanfiction. His journey and his control over Psynergy could be used in interesting ways when placed in the Naruto universe. For example, he could teach Naruto or other characters about Psynergy and how it differs from chakra.
Naruto himself is often a popular character in such fanfiction. His energetic and determined nature can be easily incorporated into stories that combine the two universes. He might be the one to bridge the gap between the Naruto world and the Golden Sun world.
Sasuke is also likely to be popular. His quest for power and revenge could be intertwined with the powers and mysteries of the Golden Sun world. Writers might explore how he would react to the new elements and abilities from Golden Sun.
In a lot of golden naruto fanfiction, there could be new characters introduced who are connected to the golden theme. For instance, a mysterious old sage who knows the secrets of Naruto's golden chakra and guides him on his journey. And of course, the villains will also be there, perhaps trying to steal Naruto's golden powers for their own evil purposes.
Blanche is also a favorite. Her flirty and southern belle nature gives a lot of room for interesting storylines. Fanfiction might focus on her love life, with all the ups and downs of her many relationships.
Often, Naruto himself can still be a main character. He might interact with the new character who has the Golden Dragon. Another main character could be the person who discovers or is born with the power of the Golden Dragon.
Naruto is surely a main character. In addition, Sasuke could also be an important figure in this fanfiction. Maybe he has a different relationship with Naruto in the context of the Breath of the Sun. He could be either a rival in trying to obtain these new powers or an ally in protecting the world from the potential threats that come with the Breath of the Sun. And don't forget about Kakashi. He might play a role in guiding Naruto and the others in this new adventure.
Obviously, Naruto is a key character. Besides him, it could feature Kakashi as he often guides Naruto. Also, there might be antagonists who are against Naruto's new role as the god of the sun. These antagonists could be power - hungry villains who see Naruto's new power as a threat to their own plans. And of course, Naruto's comrades from the Hidden Leaf Village are likely to be involved in the story in some way.
In the 'naruto power of the sun fanfiction', Naruto is the central figure. But other characters may also be significant. Shikamaru, with his strategic mind, could be involved in planning how Naruto can best utilize this power. Hinata might also be a main character as she has always been close to Naruto. Her support and unique abilities could be important in Naruto's journey with the power of the sun. And don't forget the Akatsuki members. They could be major antagonists in this fanfiction, trying to either stop Naruto from growing stronger with this power or use it for their own ends.
Sakura is quite popular too. In 2017 fanfiction, she could be depicted as an even more powerful medic - nin, or having new roles in the village. Another popular character is Kakashi. His wisdom and experience make him a great addition to many fanfiction stories.
One interesting idea could be a crossover of the Naruto world with the Golden Sun world. For example, Naruto characters might gain the ability to use Psynergy, like the characters in Golden Sun. This could lead to new and exciting battle scenarios.
Sigmar is often a very popular character. He represents a powerful and heroic figure in the Warhammer lore, so many fanfiction writers like to base stories around him and his deeds.
Lillie is often a popular character. Her kind nature and her growth throughout the story can be really interesting to explore in fanfiction.